Greetings folks....I have a question or two if you care to help. I have a 2009 base with 90k miles automatic. I recently had a metric *** ton of work done to the car. Stage 3 BTR cam, Brodix 280 (mueller) heads, LSXR 102 intake, NW 103 TB, Fast fuel rail, melling oil pump, radiator, fans, trans cooler. I already had long tube headers, xpipe (with cats), and corsa CAI, and a FTI 3200 stall. So long story short, I had all work done, and a solid street tune done but, wait for it....only knocked a tenth off my 1/8 mile time. 7.83 @ 91mph to be exact. So I took the car to a dyno tuner to see if they could knock the edge off of it and open it up. So on the first pull the car made a whopping 311hp.....he did some adjustments and the car made 351hp 331tq. He was scratching his head, because the car should be making well over 500 with this set up. He seemed to think the cats may be melted and clogged up. I plan on pulling the cats off this weekend to check them. Does anyone think there could possibly be anything else? The fuel, air, and timing are all good and the graph is perfect. I do still have the stock injectors and fuel pump but could they really be the limiting factor? Thank you in advance.....

 

Maybe they where safe on the tune, but i don't think they would let it go with high % inj duty cycle and low fuel pressure. Im cats melted as while and the tune needed to be tweaked because of more air flow. JMO

 

Post the graph

 

Definitely have an issue somewhere.I run a stage 2 BTR cam and longtubes and make close to 500RWH.Stock injectors,no headwork and a ported throttle body.I am also an automatic.

 

Don't have a copy from the tuner. I have a copy of the dyno pull though,

 

And this was the inside of one of my cats when I took them off earlier. Capable of robbing me of nearly 200hp? I punched some of that away to get a better look. I think the last tune might have been a little rich......

 

A rich tune won’t cost you 200 at the wheels let alone even 100. I would be shocked if it wasn’t traced back to the cats or even the mufflers. Easiest solution is to gut the cats and dyno the car, and if that doesn’t work drop the axle back and dyno the car. I don’t typically pay mine to 1/8 mile times so I had to look up my old ones. Your car should have dropped WAY more time than that. Just to give you an idea my c5 with a manual and a whopping 315whp went 7.62 @ 92.7mph. Hope it’s just the cats for your sake! Let us know

 

My bad, I meant the rich tune may have caused the clogging of the cats (hot). Yeah the car should be pushing wayyyy over 500 to the wheels. I ordered a catless x-pipe and 2" kooks headers to replace what I have going on. Thanks!

 

yea something wrong for sure my car ran 7.8@93 with just headers, catted Xpipe and muffler delete, Haltech CAI and tuned everything else is factory stock my car dynoed 405/408 so yea id expect yours to dyno 510-530ish and run 6s in the 1/8

 

With what you've done, I'd suspect you'd be around the 6.7 @ 106 mark unless you're still spinning at half track.
So what was your 60' time before the last mods and the latest 60' times?

 

Honestly about the same. Pre mods I was at about 2.0 and post mods my best was 1.92. I've pulled the cats off and ordered a set of kooks 2" headers and 3" catless x-pipe. Guess I will find out this weekend.

 

Have you checked the trans fluid since the converter install? Are you launching in D or S? Are you turning off TC? When you are driving normally and let off the throttle, does the car slow quickly? Do you have any smells that are heat related?
Why I ask, is that with a propped shroud as the only mod, I was cutting 2.0 short times and 7.9 at 90 in the 1/8th. With a tune, Z06 manifold/exhaust, DR's, CAI, and a 3200 stall, my short times
dropped to the low 1.7's and 1/8 mile to 7.5 at 95.
Assuming you don't have severely clogged cats, I'd be questioning what happened during the converter swap.

 

Getting solid launches at 2100-2200 rpm with solid shifts and other wise normal driving. Its just slow.

 

It appears from your first post ("I already had long tube headers, xpipe (with cats), and corsa CAI, and a FTI 3200 stall.") you had a problem well before the latest round of mods. Would I be correct in assuming you bought the car used and with those mods?

If the engine can breathe air with fuel, in and out with no restrictions (clogged air filter, incomplete throttle plate opening, pinched fuel line, low fuel pressure, clogged cats), the only remaining causes for the lack of increase from normal stock performance, are located between the converter and the tire/ground contact. That also includes the trans tune. You might want to check the trans fluid temps during normal driving and then again after 2 to 4 quick hard pulls.

BTW, with a 3200 stall, my best launches were in the 1100-1200 rpm range. I bumped it up about 100-150 for a 3600 stall and to 1700-1900 with the 4000 stall. Your 2100-2200 rpm launches give me more concerns about the converter/trans.

 

The car was stock when I got it. The stall was put in after the cam and heads were done. You cant hold your foot brake more than that? Weird. Trans fluid temps are all good, I have a derale trans cooler with fan. If the offroad x-pipe doesnt cure it I am thinking the cam may be off a tooth or something. The trans tune is on point. *EDIT- just reread what i had posted and realized I jacked that up like a football bat. Yeah, in order of installation it was: CAI, headers/xpipe, cam/heads, intake/TB, stall. Sorry about that. My brain is scrambled a bit by all of it....I spent a BUNCH of money on this and its got me a little heated.

 

I could easily hold the foot brake up to the stall limitation, however, I got my best 60' times with the rpm I posted.

While I understand your frustration, the devil is in the details. The road to success is best paved with good record keeping. I probably keep more detailed racing records than most people, which helps to run quicker too. The very first pass with my absolutely bone stock '08 on 2-2-08, netted a 2.120 60', and an 8.319 1/8th mi @89.176 in 830' DA. I never ran a 1/8th mile track, but I'm referencing those numbers for your comparison. I started out my Vette adventure similar to others. Roughly 450 passes later, I hung up my helmet in 2017 after my racing buddy crashed his car and then took ill for a year before he died. In the meantime, all the recordkeeping allowed me to see what worked and what didn't. With only boltons, my best 60' - 1.484, ET- 10.802 , MPH- 126.84, not all on the same pass or same track. Learning to do my own tuning and making adjustments at the track was one of the keys to good results.

Do you have timeslips from stock and each group of mods, so they can be reviewed in relationship to the mods at that time? I'm trying to see the overall picture vs the 2 times you've mentioned. Just throwing more parts at the problem is a hit or miss method with usually poor and costly results.

 

The stock timing at high rpm on these cars is VERY low, if the tune up didnt adjust timing--and being stock compression or possibly lower due to the larger heads, timing is going to make a HUGE difference.

The other thing that stands out is that a FAST 102 with the standard long runners will either equal a stock LS3 intake or beat it by 4-5 peak hp. I would've gotten the LS3 ported and rod modded (I have had both LSXR 102 and rod modded LS3 and I'd always take the rod modded LS3)

The other thing is that a BTR Stage 3 isn't a wild cam and a NW 103 isn't necessarily going to show a gain on an under 500 whp car.

If the cam was stabbed in a tooth off, it could EASILY be down 100 whp! I would go into the frobt ofvthe motor and if the cam wasn't degreed AT LEAST verify that it is dot to dot.

Stock 42 lb injectors should be good for 520-530 whp. Your setup should be at least 450-460 whp through the stock 6l80e.

 

Maybe I missed it but what did the other cat look like? If it looked anything like that one it could very well be your problem

 

You would think that if the cats were the culprit then that would be pretty noticeable in sound and I would imagine you’d get a lot of exhaust fumes inside the car

 

I installed 2" kooks longtubes and a cat-less x-pipe last night. I have to tighten everything down and put the plugs/wires back on and I will run it today. Hoping maybe it was a combination of the two. Have thought long and hard about that one tooth off culprit, too. If that's the case my builder said he will fix that. Thanks for the input!